The Magpul MBUS (Magpul Backup Sight) polymer sights offer a reasonably priced and durable option for iron sights on AR-15 platforms. These sights are designed to be easily installed onto a MIL-STD-1913 Picatinny/STANAG 4694 rail system and can be quickly deployed or stowed to accommodate optics. The sights feature adjustable elevation and windage, allowing for zeroing at various distances. Installation is straightforward, and the sights are noted for their relatively easy zeroing process, though precise adjustment can be challenging for some users.
Installation Procedure
The installation of Magpul MBUS sights is described as a relatively simple process, comparable to the ease of use depicted in older Geico commercials. Magpul provides instructions with the product, but the process can be summarized as follows. First, the retention screws on the sights should be removed using a flathead screwdriver or the supplied tool. The sights are then slid onto the Picatinny rail, ensuring the sight aperture and post face the rear of the firearm. When installing the rear sight, it is recommended to pull the charging handle back to facilitate installation.
According to one user report, the sights should be mounted as far apart as the rail allows, with the front sight positioned as far forward and the rear sight as far back as possible to maximize the sight radius. Another user suggests positioning the rear sight so it lays over the rearmost portion of the upper receiver, where the charging handle rests. The sights are designed to fold forward towards the muzzle when stowed and rearward towards the stock when deployed.
Zeroing the Sights
Zeroing the Magpul MBUS sights involves adjusting the elevation and windage to achieve accurate shots at a desired distance. A common practice is to begin zeroing at 25 yards and gradually move back to 50 yards or beyond. The front sight adjusts for elevation, while the rear sight adjusts for windage. Both sights include directional arrows to indicate which way to turn the adjustment dials.
The amount each click of the adjustment dial moves the point of aim depends on the sight radius – the distance between the front and rear sights. Magpul specifies that the rear sight adjusts approximately 0.7 MOA (Minute of Angle) per click with a 14.5-inch sight radius and approximately 0.5 MOA per click with a 20-inch sight radius. The front sight adjusts approximately 1.6 MOA per click with a 14.5-inch sight radius and 1.2 MOA per click with a 20-inch sight radius. Users may find it difficult to precisely determine their point of aim, particularly at longer distances, and may need to rely on smaller adjustments and iterative testing.
Materials Required for Installation
Installing backup sights requires several materials. These include the backup sights kit itself (containing both front and rear sights), a set of screwdrivers, gunsmithing tools, and optionally, Loctite or a similar thread locker. A level is also recommended to ensure proper alignment of the sights. A bench vise can be helpful for stability during the installation process, though it is not strictly required.
Additional Considerations
When installing the sights, it is crucial to prioritize safety. The rifle should be unloaded, and the chamber should be clear. The muzzle should always be pointed in a safe direction, and all firearm safety rules should be followed. When securing the screws, caution should be exercised to avoid overtightening, which could potentially damage the sights or the firearm.
Applying a small amount of thread locker to the screw threads is optional but recommended to prevent them from loosening due to recoil. Different rifles may have different mounting systems for backup sights, so it is important to identify the appropriate attachment method for the specific firearm. Consulting the rifle's manual or the iron sights kit instructions can provide this information. If existing sights are present, they must be removed before installing the Magpul MBUS sights.
User Feedback and Experiences
User feedback on the Magpul MBUS sights is generally positive. One user reported achieving a one-inch group at 50 yards after zeroing, expressing satisfaction with the results. Another user praised the durability of the polymer sights, noting they survived a drop without significant damage. Several users have recommended the MBUS Pro sights, which are constructed entirely of steel for increased durability. One user noted a past sale price of $100 for a set of MBUS Pro sights, regretting not purchasing more sets at that price.
Product Variations
Magpul offers both polymer and steel versions of the MBUS sights. The polymer MBUS sights are more affordable, while the MBUS Pro sights, made entirely of steel, offer increased durability. Magpul also produces a variety of other stock options for AR-15 platforms, including the MOE, CTR, STR, ACS, and UBR series. Detailed resources, including installation and assembly instructions, are available on the Magpul website.
Identifying Sight Type and Mounting Systems
Before beginning installation, it is important to identify the type of sights and the mounting system required for the specific rifle. Rifles may utilize dovetail mounts, Picatinny rail mounts, or other attachment methods. The rifle's manual or the iron sights kit instructions should provide this information. Removing existing sights, if present, is a necessary step before installing the Magpul MBUS sights.
Securing and Adjusting the Sights
After installing the front and rear sights, it is essential to check and adjust their alignment. A level should be used to confirm that the sights are straight and level with the rifle. Any necessary adjustments should be made to achieve proper alignment. Once the sights are aligned, the screws should be secured, and thread locker can be applied to prevent loosening due to recoil.
Conclusion
The Magpul MBUS polymer sights provide a cost-effective and relatively easy-to-install backup sighting solution for AR-15 platforms. Installation involves sliding the sights onto a Picatinny rail and securing them with screws. Zeroing requires adjusting the elevation and windage dials, with the amount of adjustment per click varying based on the sight radius. User feedback indicates generally positive experiences with the sights’ durability and ease of use. Proper installation and zeroing, along with attention to safety precautions, are essential for achieving accurate and reliable performance.